This invention relates generally to phase change memories.
Phase change memory devices use phase change materials, i.e., materials that may be electrically switched between a generally amorphous and a generally crystalline state, as an electronic memory. One type of memory element utilizes a phase change material that may be, in one application, electrically switched between generally amorphous and generally crystalline local orders or between different detectable states of local order across the entire spectrum between completely amorphous and completely crystalline states.
Typical materials suitable for such an application include various chalcogenide elements. The state of the phase change materials is also non-volatile. When the memory is set in either a crystalline, semi-crystalline, amorphous, or semi-amorphous state representing a resistance value, that value is retained until reprogrammed, even if power is removed. This is because the programmed value represents a phase or physical state of the material (e.g., crystalline or amorphous).
In order to induce a phase change, a chalcogenide material may be subjected to heating by a heater. One desirable material for forming such heaters titanium silicon nitride. Existing technology for forming titanium-silicon nitride films generally involves first forming a thin titanium nitride film using tetrakis-dimethylamino) titanium (TDMAT). Then, a silane treatment follows to add silicon to the titanium and nitride provided from the TDMAT. However, such techniques have generally provided relatively low amounts of silicon and relatively low electrical resistivity. Other techniques are also known, all of which have various problems.
Thus, there is a need for other ways for making phase change memories.